Answer:
# Program is written in python
# 22.1 Using the count method, find the number of occurrences of the character 's' in the string 'mississippi'.
# initializing string
Stringtocheck = "mississippi"
# using count() to get count of s
counter = Stringtocheck.count('s')
# printing result
print ("Count of s is : " + str(counter))
# 2.2 In the string 'mississippi', replace all occurrences of the substring 'iss' with 'ox
# Here, we'll make use of replace() method
# Prints the string by replacing iss by ox
print(Stringtocheck.replace("iss", "ox"))
#2.3 Find the index of the first occurrence of 'p' in 'mississippi'
# declare substring
substring = 'p'
# Find index
index = Stringtocheck.find(substring)
# Print index
print(index)
# End of program
